76CHAPTER 17 17.8Assuming that, on average, each aluminum atom contributes one electron, the density of charge carriers is the same as the number of atoms per cubic meter. This is AAdensityNnmass per atomM NMρ===, or ( )( )( )2336332836.0210mol2.7 g cm10 cm1 m6.010m26.98 g moln××The drift speed of the electrons in the wire is then ()428319625.0 C s1.310m s6.010m1.6010C4.010mdIvneA−−−=××××17.9(a) The carrier density is determined by the physical characteristics of the wire, not the current in the wire. Hence, nis unaffected . (b) The drift velocity of the electrons is
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